<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=1200, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <img src="" alt="" />
    <script>
        const doctype = document.doctype
        console.log(doctype)
        console.log(typeof doctype)
        const html1 = document.documentElement
        console.log(html1)   // 不是html，而是HTML元素以及里面所包含的所有节点
        console.log(typeof html1)  // object
        console.log(document.head)
        console.log(document.body)
        console.log(document.images)


        
    </script>
</body>
</html>